Chronic Obstructive Pulmonary Disease, or COPD for short, is a progressive disease of the lungs that affects millions of people each year. It is caused by blockage of the airways in the lungs, and it has no cure.
COPD relates to a number of chronic lung disorders that obstruct the airways, such as emphysema and chronic bronchitis. Emphysema occurs when some of the air sacs deep in the lungs have been damaged. This results in a smaller number of larger air sacs that have poor gas exchange capabilities.
Dyspnea, the most disabling symptom, usually begins after age 50 and worsens progressively. Large day-to-day variation in the degree of dyspnea may indicate bronchospasm. Dyspnea is more severe and more common among men. Wheezing, when present, is usually first noted when the patient is supine. Later, it may occur in any position and is usually associated with bronchospasm.
If hypoxemia develops, subtle signs of mental dysfunction, such as an inability to concentrate and reduced short-term memory, may occur. Hypercapnia may develop later and slowly lead to brain swelling and further dysfunction, resulting in confusion, lethargy, and increasing somnolence.
Signs of severe obstruction include pursed-lip breathing, which delays airway closure so that a large tidal volume can be maintained and respiratory muscles can function more efficiently; breathing in the sitting position with elbows resting on the thighs or a table, which may fixate the upper thorax and increase the curvature of the diaphragm, making breathing more efficient; and use of extrathoracic muscles (e.g. the stemocleidomastoid).
Exacerbations of obstructive bronchitis in COPD patients usually result from infection with viruses, Haemophilus influenzae, or Streptococcus pneumoniae. Fever and leukocytosis may not appear. Worsening airway obstruction often leads to increasing dyspnea. Hypoxemia or hypercapnia accompanying a respiratory infection may lead to confusion and restlessness, which may be misinterpreted as an age-related change.
In severe COPD, two stereotypes—the pink puffer and the blue bloater—help define the extremes of the disease. Most patients have features of both stereotypes. The pink puffer is typically an asthenic, barrel-chested emphysematous patient who exhibits pursed-lip breathing and has no cyanosis or edema. Usually, such a patient uses extrathoracic muscles to breathe, produces minimal sputum, and experiences little fluctuation in the day-to-day level of dyspnea. Diaphragmatic excursions are reduced, and breath and heart sounds are distant. The barrel-shaped chest is non-specific because elderly persons commonly have increased lung compliance and larger resting lung volumes. The blue bloater is typically overweight, cyanotic, and edematous and has a chronic productive cough. Elderly blue bloaters are uncommon because blue bloaters often have cor pulmonale, which rapidly leads to death if not treated appropriately.
Treatment for chronic bronchitis and emphysema is palliative, not curative. It is considered successful when it produces a favourable balance between symptomatic relief and drug-related adverse effects.
Theophylline, besides being a bronchodilator, may also be a mild respiratory stimulant.
Inhaled β2-symphathomimetics also are often effective. Corticosteroids are beneficial during acute exacerbations of bronchospasm in elderly patients with severe COPD and may reduce the length of stay in the intensive care unit and in the hospital. Long-term systemic corticosteroid therapy (prednisone 10 to 20 mg/day or its equivalent) is also beneficial in selected patients with end-stage COPD in whom all other forms of therapy are ineffective.
Hypercapnia commonly accompanies severe airway obstruction. A rapid rise in the partial pressure of CO2 (Pco2) with a drop in pH suggests that the patient has fatigued respiratory muscles and needs more intensive therapy, perhaps including ventilatory support.
Dyspnea thought to result from respiratory muscle fatigue caused by an inappropriate amount of work for a given level of ventilation or hypoxemia. Therefore, attempts are made to strengthen respiratory muscles, reduce the amount of respiratory muscle work, reduce oxygen requirements, and ensure adequate oxygen delivery. Pursed-lip breathing may reduce dyspnea by allowing for more complete emptying of the lungs, which in turn allows the diaphragm to achieve a more efficient length. There is some evidence that blowing cool air with a fan on the cheeks of patients with COPD reduces the sensation of dyspnea.
Especially patients with severe emphysema of the pink puffer type are symptom-limited due to dyspnea even at low level of activity. However, no adequate medication is presently available to treat severe dyspnea. Opioids have been suggested to be effective for the treatment of dyspnea. However, since COPD is diagnosed mainly in elderly people special care needs to be taken with regard to the correct dosing of the opioids in respect to drug-accumulation e.g. due to renal disfunction and the convenience of application. Also long term compliance is highly desirable.